1. Field of the Invention
The present invention relates to an operating device of an electronic apparatus, which is suitably used in a audio device or an air conditioner mounted on a vehicle.
2. Description of the Related Art
FIG. 4 is an explanatory view illustrating a schematic construction of a conventional operating device of the electronic apparatus. The construction of the conventional electronic apparatus will now be described with reference to FIG. 4. An operating device 52 of an electronic apparatus 51 such as a audio device and an air conditioner mounted on a vehicle comprises a printed circuit board 53, and a switch 54 attached to the printed circuit board 53.
The operating device 52 further comprises a rotary variable resistor 55, an operating shaft 56, and an operating knob 58. The operating shaft is arranged so that it is rotatable and movable in up and down directions. The operating knob is attached to the operating shaft 56 to be pushed-in and retreated corresponding to the inserted and projected operations with respect to a panel of the device, and is rotatably operated.
Further, the operating knob 58 can be manually operated, and at the time of projecting operation from the panel 57, the blast volume adjustment of the air conditioner or the sound volume adjustment of the audio device is performed by manually rotating the operating knob 58.
Further, when the operating knob 58 is manually pushed-in toward the device, the operating knob 58 comes to be maintained in its inserted operation state. And, the operating shaft 56 is moved by the operating knob 58 to operate the switch 54, and a manual mode is switched to an automatic mode.
In this manner, when the operating knob 58 is in its inserted operation state, the operating knob 58 is prevented from being inadvertently touched by a user. Thus, a previously set value is prevented from being changed.
Further, when the operating knob 58 is pushed while in its inserted operation state, the operating knob 58 retreats from the device and comes to be in its projected operation state. That is, the operating knob 58 is in its manually rotatable state.
Further, by a ‘push-push mechanism’, the operating knob 58 is pushed-in and maintained in its inserted operation state and is again pushed to be retreated from its inserted operation state to be in its projected operation state (for example, see Japanese Unexamined Patent Application Publication No. 10-53018).
However, in the conventional operating device of such an electronic apparatus, when the power of the electronic apparatus is turned off with the operating knob being in its projected operation state, the operating knob 58 is still rotatable in its projected operation state. Therefore, when a user inadvertently touches the operating knob 58, the previously set value may also be inadvertently changed.
Specifically, in the case in which the power of the electronic apparatus 51 is turned off, that is, in a state in which a new setting is not needed, the previously set value may be changed.
In the conventional operating device of the electronic apparatus mentioned above, there is a problem in that, even when the power of the electronic apparatus 51 is turned off with the operating knob 58 being in its projected operation state, the operating knob 58 is still rotatable in its projected operation state, such that when a user inadvertently touches the operating knob 58, the previously set value may be changed.